问题 单项选择题

传染性单核细胞增多症的特点()。

A.单核-巨噬细胞系统良性增生疾病

B.淋巴细胞系统良性增生性疾病

C.单核细胞系统恶性增生性疾病

D.淋巴细胞系统恶性疾病

E.浆细胞增生性疾病

答案

参考答案:B

问答题

位于清远市连州境内的“连州地下河”是闻名遐迩的旅游景点.

(1)有一位游客在洞内将装满水的矿泉水瓶中的水倒掉,然后盖紧瓶盖,很高兴地说:“我可以用这瓶气体很准确地测定洞内空气成分及含量.”你已经知道,用排水法收集到的气体常常含有较多的水蒸汽.要收集到洞内真实的空气,你对游客有什么好的建议:______.

(2)洞内不但可以欣赏如诗如画美景,还可以河上泛舟.请你设计一简单的实验方法探究洞内河水是否为硬水:______.

(3)某研究性学习小组对洞内河水进行了进一步的探究.以下是对由煮沸洞内河水产生的水垢所作的探究的一部分,请完成相关问题.

[探究课题]探究水垢的主要成分

[查阅资料]天然水中一般含有Ca2+、Mg2+、HCO3-等离子,加热时这些离子趋于生成溶解度更小的物质从而形成水垢(主要成分为碳酸盐、碱等的混合物).下面是有可能成为水垢成分的一些物质的溶解性情况:

物质Ca(HCO32Mg(HCO32Mg(OH)2Ca(OH)2CaCO3MgCO3
溶解性可溶可溶不溶微溶不溶微溶
[提出猜想]根据上述物质的溶解性表和相关知识,提出如下猜想:水垢的主要成分中一定含有Mg(OH)2和______(填写化学式,下同),可能含有Ca(OH)2和______.

下面是根据设计方案进行的实验并得出的相关结论:

在试管A中放入适量研碎的水垢,加入适量的蒸馏水,充分震荡.

①取试管A中一定量的上层清液放入另一支试管B中,加入______溶液,没有白色沉淀,证明水垢中无Ca(OH)2

②将试管A中的剩余上层清液倒出,然后试管A中加入______溶液,有气泡产生,将产生的气体通入澄清的石灰水中,石灰水变浑浊,说明水垢中一定含有碳酸盐.

阅读理解

阅读理解。

     They like using the Internet. They have lots of pocket money to spend. And they spend a higher proportion

of it online than the rest of us. Teenagers are just the sort of people an online seller is interested in, and the

things they want to buy-games, CDs and clothing-are easily sold on the Web.

     But paying online is a tricky business for consumers who are too young to own credit cards. Most have to

use a parent's card. They want a facility that allows them to spend money.

     That may come sooner than they think: new ways to take pocket money into cyber (网络的) space are

coming out rapidly on both sides of the Atlantic. If successful, these products could stimulate online sales.

     In general, teenagers spend huge amounts: $153bn (billion) in the US last year and£20bn annually in the

UK. Most teenagers have access to the Internet at home or at school-88 percent in the US,69 percent in the UK.

According to Jupiter Research, one in eight of those with Internet access has bought something online- mainly

CDs and books.

     In most cases, parents pay for these purchases with credit cards, an arrangement that is often unsatisfactory

for them and their children. Pressing parents to spend online is less productive than pressing on the high street.

They're more likely to ask "Why?" if you ask to spend some money online.

     One way to help teenagers change notes and coins into cybercash is through prepaid cards such as Internet

Cash in the US and Smart Cards in the UK. Similar to those for pay-as-you-go mobile telephones, they are sold

in amounts such as£20 or $50 with a concealed 14-digit number that can be used to load the cash into an

online account.

1. What does the word "They" in paragraph 1 refer to?

A. Sellers.

B. Buyers.

C. Teenagers.

D. Parents.

2. According to the passage, which of the following statements is TRUE?

A. More than half of the teenagers in the US and the UK have Internet access.

B. Teenagers pay for goods online with their own credit cards.

C. Most teenagers in the US and the UK have bought something online.

D. Teenagers found it easier to persuade parents to buy online than in a shop.

3. A new way to help teenagers shop online is to use ____.

A. a new machine

B. special notes and coins

C. prepaid cards

D. pay-as-you-go mobile phones

4. What is the passage mainly about?

A. Online shopping traps.

B. Internet users in the US and the UK.

C. New credit cards for parents.

D. The arrival of cyber pocket money.